The present invention relates to a high voltage generator for supplying a high voltage to a semiconductor memory device, etc.
A common memory device (IC chip, etc.) has circuits requiring a voltage higher than a supply voltage. Here, the high voltage is generally generated by using a charge pump, wherein the charge pump operates in accordance with a clock signal generated by a generating circuit.
A regulator is needed to maintain a constant output voltage of the charge pump.
In a typical regulation method, the output voltage of the charge pump is compared with a reference voltage. In the case that the output voltage is less than the reference voltage, the generating circuit generates the clock signal, and the charge pump is operated in accordance with the clock signal. However, in the case that the output voltage is greater than the reference voltage, the clock signal is not generated.
Accordingly, since the drive of the charge pump is the same even as the output of the charge pump comes close to the reference voltage, a ripple is produced in the output voltage near the reference voltage, and a large amount of current is consumed.